Curved and Straight Tonearms

rauliruegas
7,976 posts
07-04-2017 6:20am
Dear @lewm : You are rigth, it’s a J shapped design. Now, FR designed that lateral weigth balance mainly to compensate a non-perfectly leveled TT. Normally in the FR design that lateral weigth is not used if the TT is rigth on level. FR explained in its manual.

Raul, you are wrong.

The lateral balance weight should be set 5mm in from the end of the shaft on the arm pillar. This is the neutral position. It explains clearly in the manual ( page 6 ) that that if you adjust the vertical balance to 0 ( floating ), lift the turntable slightly and check whether the arm floats in or out then you adjust the balance in or out from that neutral position to compensate.

By reverse logic, if the arm mounting is perfectly level, then the weight should be at 5mm from the end of the shaft.

I have proven this by placing a gap checker under my arm board, and as expected when I tilt the arm board even a few micron the balance has to be adjusted in or out from that neutral position.

Furthermore when the arm is mounted perfectly level, and the Lateral Balance weight is 5mm in from the end of the shaft, the anti skate force required will be optimised.

It is disappointing that you would spend hours commenting on the merits of the Fidelity Research FR64S tonearm when you have clearly demonstrated that you do not understand how to set the FR64S up correctly. You hold yourself out to be an expert, when clearly you are not, and many folk who make the false assumption that that you are correct will be now setting their FR64’s up incorrectly (with the Lateral Balance removed ).

This is not the first time that you have made big mistakes in setting up your equipment, I previously highlighted to you that you had installed your Dynavector Karat Nova with the cartridge holder mounted on your arm upside down. Please find attached a video demonstrating where you went wrong on that occasion -
https://www.youtube.com/watch?v=x4o-imxZHS8

lewm
5,479 posts
07-04-2017 1:34pm
Thank you for that input, Raul.
And thanks for your response too, Nandric.
I don't have the FR64S owners manual. So I assumed that the lateral weight had to stay mounted on its post; I therefore have shoved it up against the pivot as far as it will go, on the assumption that my turntable is level AND that even in the extreme position, the lateral weight is doing something greater than zero to compensate for the J-shape, assuming that is a good thing to do.

Lewm,
Please read my previous post to addressed Raul.
Like Raul you clearly do not understand how to set up the FR64S correctly. The neutral position for the Lateral Balance weight is 5mm in from the end of the shaft. By "shoving the lateral weight up against the pivot as far as it will go" you are running the arm out of balance and your set up is compromised. In a good quality system this should be clearly audible. I would suggest you review the set up of your FR64S again to ensure that you are hearing the FR64S is it was intended to be used.  

Nandric,
There is a lot of myth in audio. The most common theory is that S shaped arms evolved from J shape to place the horizontal centre of mass of the arm tube/cartridge perpendicular to the 2 horizontal bearing points at the arm pivot closer to the centre. If you look at the J shape it places a high mass further to the inside and loads up the inside vertical bearing relative to the outside vertical bearing. As you lower the cartridge onto the record with a J shaped arm it will try and lift the inside bearing. With knife edge bearings such as the early J shaped SME's this means the inside bearing is unstable. Lateral balances are provided in some vintage arms to help correct the offset centre of mass of the arm tube/cartridge.  

Straight arm tube arms are more common now, but a key point is that along with straight arm tubes most modern gimbal bearing arms now have offset bearings; that is, the vertical bearings at the tonearm pivot have an offset angle that matches the optimum offset angle of the cartridge determined by the pivot to stylus distance.

Most vintage arms including the FR64S do not have offset bearings.
The disadvantage of non offset bearings is that when the arm goes up and down a rotational force ( twisting ) is applied to the cantilever - the use of a lateral balance never eliminates this effect, but it can reduce it somewhat.

The lateral balance on the FR64S has multiple implications, because apart from providing adjustability to the inside cancelling force, the distribution of mass around the bearing housing alters the loads on the bearings, and ultimately the forces, both rotational and lateral, on the cantilever as the arm moves up and down and back and forth on eccentric records.

For this reason rather than second guess ALL the engineering considerations that have gone into the design of the arm, one should set an arm up as per the manual in the first instance. We have a saying "a bad workman blames his tools" - this is so very true of poor tonearm and/or cartridge set up that all too often leads to indifferent results. 

     
     

rauliruegas
7,978 posts
07-05-2017 3:12am
Dear @dover : Of course I know exactly how to set up that arm.

My post to @lewm was taking in count what the manual says:

""" Note 2): the lateral balance device is provided to correct for the sideways tendency in tonearm movement that occurs when the TT cabinet is not used on a horizontal stand. Practically speaking no problems will occurif the TT is installed level. Therefore, you ordinary don’t need to pay too much attention to this adjustement ".

Raul,
It is clear that you do not know how to set up the FR64S correctly.
"Adjustment" in English means 'do not move from the neutral position'.
The 'neutral position' for the Lateral Balance is 5mm in from the end of the shaft as is explained clearly in the manual.

rauliruegas
7,976 posts
07-04-2017 6:20am
Dear @lewm : You are rigth, it’s a J shapped design. Now, FR designed that lateral weigth balance mainly to compensate a non-perfectly leveled TT. Normally in the FR design that lateral weigth is not used if the TT is rigth on level. FR explained in its manual.

In this post you were wrong when you advised people to "not use" the lateral balance.

As regards the "Dynavector Karat Nova" you say 

rauliruegas
7,978 posts
07-05-2017 3:12amI owned the Dyna Karat that comes with a " terrible/poor " dedicated headshell and I never used the cartridge with that headshell .

Raul,
How is it possible for you to conclude that the dedicated headshell provided with the Dynavector Karat Nova is "terrible" when you say that you never used it. That conclusion would appear to be fanciful at best.

rauliruegas
7,978 posts
07-05-2017 3:12amI
the very high level of frustration you have with me for long time because because many times showed you level of ignorance in discussions. That level of ignorance is different from my ignorance levels.

Raul,
Thank you for those kind words. I leave you with a quote to reflect upon from Daniel Boorstin -
“The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.”

genisis,
I couldn't agree more with your observations. I discovered how sensitive my FR64S was to the positioning of the Lateral Balance weight by accident. My Final Audio Parthenon TT uses a gunmetal arm board and has no adjustment - the TT has no compliant materials in its structure and relies on precision machining of all components. One of my aftermarket custom machined arm boards was out only by a few thou of an inch and the net result was higher than expected anti skate force required. Experimenting around quickly highlighted that when the few thou error in the arm board was corrected the Lateral Balance ended up smack bang back in the recommended neutral position described in the manual and the anti skate minimal. This also suggests that the bearings in my particular sample are very sensitive.

I currently own the following arms - Eminent Technology ET2, Naim Aro, Dynavector 501, Micro Seiki MA505iii (low effective mass) and 2 Fidelity Research FR64S'.  My preferred arms for ultimate performance are the ET2 and Naim Aro, but each arm has its plus' and minus' - the results can depend very much on cartridge matching, turntable and setup and this is the point often missed. I use the FR64S with an Ikeda Kiwame and Koetsu Black. My current reference is Naim Aro/Dynavector Karat Nova 13D or Eminent Technology ET2/whatever.

Lewm,
You are absolutely correct. Oil in the bearings will increase stiction and can even degrade the sound substantially at worst. I have no issue if Raul thinks that the FR64S is the worst arm he has ever heard in his system. However as you point out he cannot possibly ascribe the poor results he has experienced in his system to an attribute of the arm unless he has deconstructed the arm and run extensive lab tests trialling changes to the arm and measuring the results to isolate what each component and design element within the arm is contributing to any resonances generated by the cartridge on playback. Even then, the results can vary depending on cartridge, set up and arm board termination. Rauls' observations are only relevant within the context of the system in which has has heard the arm. He does not seem to grasp this concept and continues to make sweeping conclusions as you have alluded to.
With my Naim Aro the arm tube is purposely undamped, the designers intent is to transfer resonances as fast as possible to the unipivot bearing, where the bearing design and low centre of gravity from the underslung counterweight are designed to add mechanical damping by about 6-8db, from whence the residual is sunk to the arm board via mechanical grounding..